The storm’s maximum sustained winds decreased to near 100 km/h early Tuesday with gradual weakening expected over the next two days.

The U.S. National Hurricane Center says Bertha is forecast to pass midway between the American East Coast and Bermuda later in the morning.

The storm is centred about 765 kilometres west of Bermuda and was moving north-northeast near 35 km/h.

The Canadian Hurricane Centre in Halifax said the storm was expected to move well south of Nova Scotia with its northern tip expected to spread cloud over the province.

The centre said rain from the post-tropical phase of the storm may affect the southeastern portion of Newfoundland.

Winds are expected to remain offshore, although there is a small chance they could affect southeastern Newfoundland on either Wednesday or Thursday.

Ocean swells are also expected along the Atlantic coast of Nova Scotia and in Newfoundland with Bertha likely bringing gales to the Southern Maritimes Marine District and the Grand Banks off Newfoundland.

The centre said Bertha was expected to gradually weaken due to strong southwesterly wind shears and cooler sea surface temperatures.

But forecasters said there was a large degree of uncertainty with the storm because it could merge with a trough of low pressure.

On Sunday, the storm buffeted parts of the Bahamas and the Turks & Caicos with rain and gusty winds, after passing over the Dominican Republic. Earlier, it dumped rain on Puerto Rico.